The United States said Thursday "time is wasting" in seeking a solution to the dispute over Iran's nuclear activities as Tehran has failed to respond constructively to Western proposals, reported dpa.
"We believe there is still time and space for diplomacy," US Ambassador Susan Rice told a UN Security Council meeting on Iran's nuclear programme.
"However, the onus is on Iran to respond constructively," Rice said, adding that Washington is seeking a "clear, united resolution" to Iran's uranium enrichment programme, which she said has advanced beyond the 20-per-cent enrichment needed for civilian use of nuclear energy.
Iran has regularly insisted that it has no intention of creating a nuclear weapons programme.
Rice said the five permanent council member countries - the US, Russia, China, France and Britain - plus Germany have proposed reciprocal steps aimed at solving the nuclear dispute. She said Iran has so far not responded.
The warning comes as the US and allies are carrying out massive naval drills in the Gulf, which observers say are related to mounting tensions with Iran.
The manoeuvres, codenamed IMCMEX-12, involve clearing mines that may be deployed by an hypothetical "enemy" to block shipping traffic, according to military commanders.
Arab countries, mainly Saudi Arabia, as well as Britain and France are participating in the manoeuvres, expected to run until later this month.
Iran itself has said it will hold stage a major defence exercise next month.
Previously, Tehran has warned it would close the Strait of Hormuz if attacked. An estimated 20 per cent of global oil exports pass through the strait.
Israeli Prime Minister Benjamin Netanyahu has recently prodded the administration of President Barack Obama to draw "red lines" for Iran over its disputed nuclear programme.
Netanyahu demanded in a round of interviews at the weekend that Washington and the rest of the world tell Tehran that, if Iran crossed a certain point, military force would be used against it.
But Obama, seeking re-election, said he would not impose red lines or a deadline on Tehran.
An Israeli newspaper reported Thursday that Washington has warned Israel that if it attacked Iran's nuclear sites, this could prompt Egypt and Jordan to annul their peace treaties with the Jewish state.
"Today the Arab leaders do not control their peoples, the street controls the leaders," Yedioth Ahronoth quoted a "senior Israeli official" privy to the warning as saying.
"An Israeli strike is just what the Iranians need. The entire Arab and Muslim world will take to the streets."
The Egyptian and Jordanian governments would be unable to withstand the mass pressure, even though they too strongly oppose a nuclear Iran and perhaps even hope for an Israeli strike, the official said.
A US embassy spokesman in Tel Aviv had no comment.
An Israeli official, speaking on condition of anonymity, told dpa that "in the Arab world, governments are just as concerned as we are, very concerned about the threats posed by the Iranian nuclear programme."